Bathroom exhaust fans are also a prime location to sample.

They were either elderly folks living on a small pension or exhausted people living paycheck to paycheck.

@Derek McInnis   I would exhaust all your local resources.. person to person resources and then read about the people you want to become.  

I've exhausted all other options.

There is minimal equity because we had a refi cash out and rehabs funds have been exhausted. 

If a rental or a flip you need to know what other bathrooms look like in the area as to finishes and quality expected.Example it has an older insert tub.You want to rent out.You find out that as long as the old tub and shower is clean tenants will pay 800.With a new tub and shower they will pay 820 a month.Putting in new say costs 1,500 for example.It will take you a 20 a month 75 months (over 6 years) to recover your money.So your answer depends on what you are doing with the property.Not just for the mold but the fixtures,valves,toilet,and supply lines for the sink and toilet etc.If you get a contractor to fix this they will charge a mint.If you get a mask and take it out and just put cement board up you should be fine.You need to make sure exhaust fan works,is proper size and suction rate for that size of the bathroom,and is properly vented to the outside of the property.Make sure roof is properly vented as that could cause sweating and mold problems.If you look into the attic and see mold on the underlayment of the roof boards then you either have a roof leak or a breathing problem.The roof vents for air going in and out (cycling) could be too small ,in wrong location,or too close together.Hard to say without being there.No legal advice.

Once you have exhausted that source find private money.

Umbrella kicks in when regular insurance gets exhausted. 

This is not an exhaustive list and you'll likely need to go down to your county Recorder's Office and personally view what liens are attached to the property. 

Also, I never knew the exhaust fan even existed in the bathroom.